Robb Kulin has resigned halfway through his two years of NASA training

For the first time in 50 years, an in-training astronaut candidate has resigned from The National Aeronautics and Space Administration (NASA). The 2017 astronaut candidate Robb Kulin has reportedly resigned halfway through his two years of NASA training.

Thirty-four-year-old Kulin began training at NASA’s Johnson Space Center in Houston in August last year. He was one of the 12 astronauts chosen last summer from a record 18,300 applicants. He was working as a senior manager for flight reliability at SpaceX when he got selected for the astronaut training.

Kulin grew up in Anchorage, Alaska. He has previously worked as a commercial fisherman in Alaska and an ice driller in Antarctica. He studied in California and graduated with a doctorate in engineering from the University of California-San Diego in 2010.

SpaceX and Boeing are jointly developing NASA’s commercial crew capsules, due to launch within the next year. If Kulin completed his training, he could have got a chance to fly on a vehicle that he helped design at his last job. He joined SpaceX in 2011.

NASA spokesperson for the Johnson Space Center, Brandi Dean, said Kulin has resigned from the program due to personal reasons. It’s still unclear exactly why he took the step. The resignation, which is effective Aug. 31, 2018, would leave only 11 members in NASA Astronaut Group 22, which is nicknamed “The Turtles.” The remaining members are Kayla Barron, Raja Chari, Zena Cardman, Bob Hines, Warren Hoburg, Jonny Kim, Jasmin Moghbeli, Loral O’Hara, Frank Rubio, Matthew Dominick, and Jessica Watkins.

Notably, the U.S. space agency has already indicated that the potential astronaut won’t be replaced.

The last time astronauts-in-training resigned from NASA was back in 1968. Brian O’Leary resigned in April 1968 due to the lack of spaceflight prospects and a few months later John Llewellyn resigned after failing to make progress piloting jets.